Improved Centrifuge Designs for High Cake Solids

The new generation of advanced centrifuges pioneered by Humboldt Wedag can readily produce 30 ± 2% TS cake on most raw and digested primary and waste activated sludge, wherein the primary fraction is 40-60% of the total mass. While the centrifuge capacity is reduced by about 40% and the chemical costs are increased 20-50%, the overall sludge processing costs can be substantially reduced. This improvement in cake solids will be especially beneficial for incineration, composting and longer haul land disposal operations. Equally significant is the potential to upgrade existing installations by installing higher horsepower backdrives. This simple upgrade may increase cake solids 5-8 percentage points at a relatively modest cost and should be investigated as a first option. These and other aspects of the subject are discussed, including testing of the upgraded centrifuges.